bulb

Everyday

1. A bulb (light bulb) is the glass part of a lamp that gives out light when electricity flows through it. tree →
2. A bulb is the round underground part of some plants, like tulips, onions and daffodils, from which a new plant grows. tree →
3. A bulb is any round, swollen part, like the bulb of a thermometer. tree →

In the lessons

In science, a bulb is a component in an electric circuit: it lights only when the circuit is complete; more batteries make it brighter, more bulbs in a line make each dimmer. In nature lessons, bulbs are planted in autumn and flower in spring; they store food for the plant. Phrases: light bulb, energy-saving bulb, LED bulb, a light-bulb moment (a sudden good idea), plant bulbs.

Examples

• The bulb lit up when we closed the switch. tree →
• Dad changed the bulb in the kitchen. tree →
• We planted tulip bulbs in the autumn. tree →
• An onion is a bulb. tree →
• The red liquid rose from the bulb of the thermometer. tree →
• I had a light-bulb moment and solved the puzzle. tree →
• The drops penetrated through the snowy covering down into the earth, and touched the flower-bulb, and talked of the bright world above. tree →

Note

Countable: one bulb, two bulbs. Never touch a bulb that has just been on; it can be very hot. Let an adult change bulbs, with the power off. In a circuit diagram a bulb is drawn as a circle with a cross inside.