The floating egg: science and the zero conditional
Children read the instructions for a simple salt-water experiment, predict and watch what happens, then explain science facts with the zero conditional.
At a glance
- From
- Level 2, Moving Up English: Week 21, Science and nature
- Grammar
- zero conditional (If you..., ...)
- Key language
- If you put an egg in tap water, it sinks. / If you add salt, it floats. / sink, float, stir, add, pour, a spoonful, a glass
- Children make
- An experiment record and four zero conditional sentences.
- Class size
- Works with 10 to 50 children; pair and group steps say how to scale.
Objective
Children read and follow instructions, and use the zero conditional to explain things that are always true.
Success criteria for children
- I can follow written instructions in order.
- I can make zero conditional sentences.
- I can explain what happened in an experiment.
Timing: 60 minutes
| Minutes | Stage | What happens |
|---|---|---|
| 0 to 5 | Warm-up: sink or float? | Children guess if classroom objects sink or float. |
| 5 to 13 | Instruction words | Teach fill, put, add, stir, watch with actions. |
| 13 to 25 | Reading: the instructions | Read the experiment; order the steps; predict. |
| 25 to 35 | Demonstration | Do the experiment at the front; children narrate. |
| 35 to 47 | Zero conditional | If + present, present for things that are always true. |
| 47 to 60 | Writing and exit ticket | Write the result and own If sentences; exit ticket. |
Materials
- For a demonstration: one fresh raw egg, a tall clear glass or jar, tap water, salt, a spoon
- Worksheet, pencils
- Walking water experiment (free, linked from Week 21)
- Saving water (free, linked from Week 21)
- Nature flashcards (free, linked from Week 21)
Before the lesson: Try the experiment at home first: fresh eggs sink in tap water, and the egg usually floats after several spoonfuls of salt have dissolved. If an egg floats in tap water before you add salt, it is old; use a fresher one. Have a cloth ready. If you cannot get an egg, use the text only and show the result by drawing.
Step by step, with teacher talk
0 to 5 minWarm-up: sink or float?
- Hold up a pencil, a coin, a leaf, a key. Children show thumbs up for float, down for sink. Teach "sink" and "float" with hand movements.
5 to 13 minInstruction words
- Mime each verb with the real objects. Children copy the action and the word.
- If I stir, do I move the spoon round and round or up and down? (Round and round.)
13 to 25 minReading: the instructions
- Children read the text and do task 1 (order the steps).
- Before the demonstration, they write a prediction: "I think the egg will..."
25 to 35 minDemonstration
- Follow the instructions exactly as children read them aloud to you, one step each.
- Pause after the egg sinks. Then add salt a spoonful at a time while the class counts. Ask "What's happening?"
"Read me step one. OK, I'm filling the glass... Now what? Step two..."
35 to 47 minZero conditional
- Write: If you put an egg in tap water, it sinks. Underline both present verbs.
- Show other always-true facts: If you heat ice, it melts. If you mix blue and yellow, you get green.
- Children match the halves in task 2 and check with a partner.
- Is this true only today or always? (Always.)
- Can we change the order? "The egg floats if you add enough salt." (Yes, and then no comma.)
47 to 60 minWriting and exit ticket
- Children complete task 3, then the exit ticket below.
Differentiation
Support
- Give the experiment steps as four pictures to order before reading.
- Provide sentence halves to match before writing their own.
Stretch
- Explain why: salt water is heavier than tap water, so it pushes the egg up more.
- Plan a new experiment and write the instructions.
- Write a sentence with "unless" or "when" instead of "if".
Reading passage
You need: a fresh egg, a tall glass, tap water, salt and a spoon.
What to do: First, fill the glass with tap water until it is about three quarters full. Next, put the egg in the water very gently. Watch what happens. Then take the egg out with the spoon. Add a big spoonful of salt and stir until you can't see the salt. Put the egg back in. If it still sinks, take it out and add more salt, one spoonful at a time.
What happens? If you put a fresh egg in tap water, it sinks to the bottom. If you add enough salt to the water, the egg floats. This happens because salt water is heavier than the same amount of tap water, so it pushes the egg up more strongly.
Remember: wash your hands after you touch a raw egg.
Questions
- What do you need for the experiment?
- How full should the glass be?
- What happens to a fresh egg in tap water?
- What should you do if the egg still sinks after one spoonful of salt?
- Why does the egg float in salty water?
Printable worksheet
Prints on its own A4 page. Use Print the worksheet above, or print the whole plan and the worksheet starts on a new page. One copy per child, or one per pair to save paper.
The floating egg
1. Put the steps in order. Write 1 to 5.
- Add salt and stir.
- Fill the glass with tap water.
- Put the egg back in and watch.
- Put the egg in gently. It sinks.
- Take the egg out with a spoon.
2. Match the two halves.
| 1. If you heat ice, | ● | ● | a. it sinks. |
| 2. If you mix blue and yellow, | ● | ● | b. it dies. |
| 3. If you put a fresh egg in tap water, | ● | ● | c. it melts. |
| 4. If you don't water a plant, | ● | ● | d. you get green. |
3. My experiment.
I predicted that the egg would .
What happened? If you , the egg .
Write two more true If sentences about science or nature:
Answer key
Reading passage questions
- A fresh egg, a tall glass, tap water, salt and a spoon.
- About three quarters full.
- It sinks to the bottom.
- Take it out and add more salt, one spoonful at a time.
- Salt water is heavier than the same amount of tap water, so it pushes the egg up more.
Worksheet
- 1: 4, 1, 5, 2, 3.
- 2: 1c, 2d, 3a, 4b.
- 3: answers will vary. Model: If you add enough salt, the egg floats.
Exit ticket
Finish this sentence in two different true ways: "If you drop a glass, ..." and "If it rains, ..."
Homework
With an adult, try the experiment at home or test five objects in a bowl of water. Write "If you put a ___ in water, it ___." for each one.
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- Level 2, Week 21: Science and nature (the curriculum week this plan comes from)
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