People, pollution and frogs
People change habitats. Smoke from vehicles and factories pollutes the air. Litter, oil and waste can pollute canals, rivers and the sea. Dirty water and air make it harder for plants and animals to survive. Frogs are amphibians. Tadpoles live in water and breathe with gills. Adult frogs breathe with lungs and also take in oxygen through their thin, damp skin. Because their skin takes things in from the water, frogs are hurt by polluted water, and scientists watch frogs to see whether a pond is healthy. In Egypt, the Nile and the canals give life to farms and cities, so keeping them clean matters. We can put litter in bins, reuse bags, never throw rubbish in a canal and save water. Scientists explain ideas with three parts: a claim (the answer), evidence (what we saw or measured) and reasoning (why the evidence supports the claim).
| Part | What it says |
|---|---|
| Claim | Huddling helps penguins survive the cold. |
| Evidence | Penguins in the middle of a huddle stay warmer than those at the edge. |
| Reasoning | Standing close shares body heat and blocks the wind, so less heat is lost. |
Clean-up survey. With a grown-up wearing gloves, walk around your school yard or street for ten minutes. Do not pick up glass or anything sharp. Tally the litter you see: paper, plastic, food, other. Draw a bar graph. Say one change that would reduce the most common kind.